document function

impd

@@ -837,6 +837,10 @@ grep_mpd_dir() {
 }
 
 choose_mpd_dir() {
+	# Try to find the user's music directory.
+	# If "music_dir" is set in the config file, it takes precedence.
+	# Otherwise, the directory is set to the value from mpd's config.
+	# Different fallbacks are tried in other cases.
 	local dir
 	for dir in "$music_dir" "$(grep_mpd_dir)" "$(xdg-user-dir MUSIC)" ~/Music ~/music; do
 		dir=${dir/\~/$HOME}